Carbide Formation and Growth Kinetics Enhanced by Tensile Stress and Elevated Temperature Intergranular Cracking in 2.25Cr-1.5W Heat-Resistant Steels

The carbide growth kinetics enhanced in grain interiors is mainly due to the increased diffusivity in the direction normal to the tensile stress. The accelerated kinetics at the grain boundaries normal to the tensile stress is due to the increased grain boundary energy and the widened grain boundary path producing the increased diffusivity in the direction normal to the tensile stress. A strong segregation behavior of impurities to the grain boundary carbide interfaces follows the enhanced grain boundary carbide growth kinetics.